package cwbjsdk.cwsdk.util;

import java.util.Arrays;

/**
 * Created by leonn on 2017/6/22.
 */

public class SMS4Class {

    private final static int ROUND = 32;

    private static short sbox[] = {
            0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d,   0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
            0x2b, 0x67, 0x9a,  0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
            0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a, 0x33, 0x54, 0x0b,   0x43, 0xed, 0xcf, 0xac, 0x62,
            0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8,   0x95, 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
            0x47, 0x07, 0xa7,   0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
            0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f,  0x4b, 0x70, 0x56, 0x9d, 0x35,
            0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1,   0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
            0xd4, 0x00, 0x46,   0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
            0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2,  0xce, 0xf9, 0x61, 0x15, 0xa1,
            0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a,  0x55, 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
            0x1d, 0xf6, 0xe2,   0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
            0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a,   0x72, 0x6d, 0x6c, 0x5b, 0x51,
            0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc,   0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
            0x0a, 0xc1, 0x31,   0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
            0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1,  0x09, 0xc5, 0x6e, 0xc6, 0x84,
            0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d,   0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
    };


    private static int fk[] = { 0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc };

    private static int ck[] = {
            0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
            0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
            0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
            0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
            0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
            0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
            0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
            0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
    };

    public static int rotateLeft(int x, int n) {
        return ((x << n) | x >>> (32 - n));
    }

    private static int ltrans(int b) {
        return b ^ (rotateLeft(b, 2)) ^ (rotateLeft(b, 10)) ^ (rotateLeft(b, 18))   ^ (rotateLeft(b, 24));
    }

    private static int keyLtrans(int b) {
        return (b ^ rotateLeft(b, 13) ^ rotateLeft(b, 23));
    }

    private static int substitute(int x) {
        return (sbox[(x >>> 24) & 0xff] << 24)
                ^ (sbox[(x >>> 16) & 0xff] << 16)
                ^ (sbox[(x >>> 8) & 0xff] << 8)
                ^ (sbox[(x) & 0xff]);
    }

    private static int ttrans(int x) {
        return ltrans(substitute(x));
    }

    private static int keyTtrans(int x) {
        return keyLtrans(substitute(x));
    }


    public static int[] calcRk(int[] mainKey) {
        int rk[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        int[] key=new int[4];
        key[0] = mainKey[0];
        key[1] = mainKey[1];
        key[2] = mainKey[2];
        key[3] = mainKey[3];

        key[0] ^= fk[0];
        key[1] ^= fk[1];
        key[2] ^= fk[2];
        key[3] ^= fk[3];
        for (int i = 0; i < ROUND; i++) {
            rk[i] = key[0] ^ keyTtrans(key[1] ^ key[2] ^ key[3] ^ ck[i]);
            key[0] = key[1];
            key[1] = key[2];
            key[2] = key[3];
            key[3] = rk[i];
        }
        return rk;
    }

    private static void roundFun(int[] input, int rk) {
        int tmp = input[0];
        input[0] = input[1];
        input[1] = input[2];
        input[2] = input[3];
        input[3] = tmp ^ ttrans(input[0] ^ input[1] ^ input[2] ^ rk);
    }

    public static void reverse(int[] input) {
        int tmp;
        tmp = input[0]; input[0] = input[3];input[3] = tmp;
        tmp = input[1];    input[1] = input[2];input[2] = tmp;
    }

    /**
     * 加密
     * @param plain 明文
     * @param key 密钥
     * @return 密文
     */
    public static int[] encrypt(int[] plain, int[] key) {
        int[] plainData= Arrays.copyOf(plain, plain.length);
        int rk[] = calcRk(key);
        for (int i = 0; i < ROUND; i++) {
            roundFun(plainData, rk[i]);
        }
        reverse(plainData);
        return plainData;
    }


    /**
     * 解密
     * @param cipher  密文
     * @param key  密钥
     * @return  明文
     */
    public static int[] decrypt(int[] cipher, int[] key) {
        int[] cipherData=Arrays.copyOf(cipher, cipher.length);
        int rk[] = calcRk(key);
        for (int i = 0; i < ROUND; i++) {
            roundFun(cipherData, rk[31-i]);
        }
        reverse(cipherData);
        return cipherData;
    }


    public static String HexTostr(byte[] hex, int hexlen) {
        String str = "";
        if (hex.length == 0)
            return str;
        for (int i = 0; i < hexlen; i++) {
            String buf = Integer.toString(hex[i] & 0xFF, 16).toUpperCase();// &
            // 0xFF去掉负号
            if (buf.length() != 2)// 补位
            {
                str += "0" + buf;
            } else
                str += buf;
        }
        return str;
    }

    public String GetStrValueFromInt(int val)
    {
        byte[] tdata  = new byte[4];

        tdata[0] = (byte)(val>>24);
        tdata[1] = (byte)(val>>16);
        tdata[2] = (byte)(val>>8);
        tdata[3] = (byte)(val);

        String strval  = HexTostr(tdata,4);
        return strval;
    }

    public static byte[] StrToHex(String str) {
        if (str.length() % 2 != 0)
            return null;
        byte[] ret = new byte[str.length() / 2];
        StringBuffer buf = new StringBuffer(2);
        int j = 0;
        for (int i = 0; i < str.length(); i++, j++) {
            buf.insert(0, str.charAt(i));
            buf.insert(1, str.charAt(i + 1));
            int t = Integer.parseInt(buf.toString(), 16);
            ret[j] = (byte) t;
            i++;
            buf.delete(0, 2);
        }
        return ret;
    }

    public int SetStrValueToInt(String strval)
    {
        byte[] tdata =  StrToHex(strval);

        int  val;

        val =   (tdata[3] & 0xFF )|((tdata[2] & 0xFF) << 8) | ((tdata[1] & 0xFF) << 16) | ((tdata[0] & 0xFF) << 24);

         return val;

    }

    public  String  SMS4ValueToString(int [] c) {

        if(c.length != 4) {
            return   null;
        }
        return  (GetStrValueFromInt(c[0]) + GetStrValueFromInt(c[1]) + GetStrValueFromInt(c[2]) + GetStrValueFromInt(c[3]));
    }

    public  int[]   SMS4ValueToIntArray(String s) {

        int[]  a = new int[4];

        if(s.length() != 32) {
            a[0] = 0;
            a[1] = 0;
            a[2] = 0;
            a[3] = 0;
            return  a ;
        }

        a[0] = SetStrValueToInt(s.substring(0,8));
        a[1] = SetStrValueToInt(s.substring(8,16));
        a[2] = SetStrValueToInt(s.substring(16,24));
        a[3] = SetStrValueToInt(s.substring(24,32));
        return  a;
    }

}
